Project Squirrel

[Outlaw]

Well the math I went off of was the calculation from the FRA rules and regs.

The battery is a 35C series, and it does 2700 mAh, which is specified on the front of the battery.

Which means, by going off of the multiplication of that, 35 x 2700 = 94500. Which means by logic, that brings it to 94.5 amps.

It's Burst rating is 45C according to the hobbyking website. So if I make it 45 x 2700 = 121500. So that in logic makes it 121.5 amps.

Sp somewhere in between those two? I've looked at Halfords and their 110 amp fuse is a strip fuse, which doesn't seem to be the right kind of fuse... which is here.

Their 100 amp fuse however looks a little something like this.

And Maplin doesn't seem to hold any that's suitable for that kind of amperage from what I've seen.

All this math is making my head spin... why did I flunk my systems and control class...

[daveimi]

The fuse is mostly to stop the electronics pulling too much from the lipo, lipo gets hot and then catches fire. So the rules say you must have a fuse for the maximum the lipo can supply, but in reality you won't get near that with a pair of drill motors. They pull about 30 amps a pair tops. So in that case you could put a 30 amp fuse in and roberts ya mothers brother. If you have weapon motors as well, add the current to 30 ish for the drive and buy for that. It's as complicated as you make it.

[Outlaw]

David, that's made things a lot more easier. I can easily find fuses as such in Halfords. And if not in Halfords, then I'll just look to ebay. Quick question... yes, I know, another one, but I always just want to make sure. One battery leading into a ESC controlling the two drive motors, will I need two fuses or just the one for that?

So that'd make my shopping list...

Shorter M6 bolts, as the ones I have won't fit the drive motor mounts.
2/3 fuse holders, one for the drive, one for weaponry.
2 30 amp fuses plus spares
24v strip LED lights
And a pair of wheels.

Once that's all done, I can get on to getting on with the weapon system.

[Outlaw]

Back at it again with the LEDs... Would connecting say... a couple of these just after the 30 amp fuse work or will the bulb just blow straight away? And will I need some sort of mounting board to go along with them?

[McMad]

My understanding of the rules is that you need one fuse and it sits between the battery and ESC(s). So following the wire along you have battery - fuse - Power LED - ESC(s).

[Outlaw]

My understanding of the rules is that you need one fuse and it sits between the battery and ESC(s). So following the wire along you have battery - fuse - Power LED - ESC(s).

Yeah, I figured that out as well, but all I'm wanting to know is that if the LEDs I linked in my previous post is suitable for the task at hand, or if there's any out there that do the job better and if so, I'd love to know what it'd be.

[Outlaw]

So I measured the radius of drive motor axle to floor, and it's about roughly 5 and 1/2 to 6 cm off the floor, which means best bet for wheels is possibly a 120mm-125mm wheel maybe? And seeming as that's the case, would this be a suitable wheel to go for here?

If not, what are some other suitable wheels at that size, considering that I don't have a lot of space to work with, and I'm wishing to make it a direct drive from axle to wheel.

[McMad]

I don;t think those LED's are suitable on their own, they'd need a resistor to protect them as they can only take a few volts. Someone with a better understanding of the voltages can suggest a value.

[Roboteernat]

You will need a resistor to reduce the current correctly, something like a 560 Ω Resistor will be suitable, if you go this route I have several am happy to stick in an envelope for you.

Otherwise if you want plug and play...

Heres some someone has pre made http://r.ebay.com/DBUsuv for single led a nice 10mm will be fine.
Otherwise look for '12 v LED'

If you do want an LED with resistor, I can see what I have got and send one to you too...

[RogueTwoRobots]

Just get some 12V LED strip on eBay. It comes with a sticky backing for easy adhesion and you can just wire them up in series to drop the voltage to them. I run my robots on 5S/6S with series linked LEDs and they're absolutely fine. No resistors or anything to worry about. They're also a lot brighter and more visible than normal LED bulbs.

[Roboteernat]

I still have the offer for the LED strip if you would like a length? 12v or 24v rated. (in white tho)

[Outlaw]

Hi hi, sorry for the late reply.

I managed to get the fuses sorted out, went down to halfords and bought a set of 30 amp mini blade fuses, along with holders. Means more space for components at least.

Thank you for the insight Jamie, at least I don't have to mess around with resistors, which is one less thing to buy.

And Nat, I'll give you a nudge a little later to see if I can buy a couple of strips from you. Have to consult with my mother before hand, so she knows what I'm spending my money on and such haha. Which means I'm interested but I'll have to either contact you later on today or tomorrow.

[Outlaw]

Alright... more than likely the last time I'll bother this particular thread, as the item in question is castors... what'd be a decent castor for featherweights? And if so, would it be available with M6 sized holes too for convenience sake?

[RogueTwoRobots]

I don't know of any featherweights that run castors, even heavyweights don't tend to run them. They're often too weak for robot combat so most people either just let the leading edge of the robot/chassis run on the floor, or mount a low-friction material (eg. Nylon) skid plate on the underside of the robot.

[Outlaw]

Ah, fair enough, fair enough. I'll try to get maybe some kind of skid plate instead then. Might end up being part of a plastic bottle or some cut up aluminium soda cans, and try and smooth some of them out. If that doesn't work, I'll have to try and think of something else. Thank you for the information Jamie.